Slack tazb-up device



May 25 1926. f

` D. M.' RUSSELL ET AL SLACK TAKE-UP DEVICE Filed Feb s, 1925 2Sheets-Sheet 1 QN AQ mwN $5 %N May 25 1926. 1,586,047

y D. M. RUSSELL ET AL SLACK TAKE-UP DEVICE Filed Feb. s, 1925 2sheets-Sheet 2 patented ll/lay 25;, EQ2@ narran Lsiaett PATENT OFFICE.

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Application filed February 3, 1925. Serial No. 6,595.

This invention relates to Vslack take-up devices and more particularlyto a device of this lcharacter primarily intended for use in connectingbrake levers and brakes.

An important object ol: the invention is to provide meanswh'ereby theconnection between the lever and objective is shortened during theworking stroke.

A further object oi the invention is to provide a device of thischaracter in which, when the working stroke exceeds a prede terminedlength, the connection is held in its shorinnded position so that thenext succeedinl` working stroke will be shortened.

A still iurther object of the invention is to provide means whereby theelement accomplishing the shortening will automatically take-up as to.length so as to remain at all times at the .proper length for thedistance through which it must operate.

A further and more specific object of the invention is to provide aconnection between the. lever and objective including a rotatable partwhich, when rotated, varies the eliective length of the vconnection andthe connection between the rotatable partand lever partially rotatingthe same upon each operation of the lever.

A still further object of the invention is to provide means forpreventing return motion of the rotatable part when this motion exceedsa predetermined amount and at the same time shortening the connectionbetween the rotatable part and the lever so that it remains of the sameor proper effective len h.

These and other objects we attain by the construction shown in theaccompanying drawings, wherein for the purpose of illusteration yisshown a preferred embodiment of our invention and wherein Figure 1 is aside elevation of slack takeup mechanism constructed in accordance withour invention applied to connect a lever and brake;

Figure 2 is a plan view thereof;

Figure 3 is an enlarged detailed view of the central take-up mechanism,one of the Side ends being removed;

Figure 4 is a detailed sectional view of the takeup mechanism of thelink 16; and

Figure 5 is a side elevation of a modified form of the invention.

Referring now more particularly to the drawings, the numeral indicates alever pivoted at one end as indicated at 11, and

12 a brake or other element to be operated from the lever and to bemoved to operated or set position by movement of the lever in thedirection of the arrow A of Figure 1. The connection between the leveryand member to be operated comprises primarily a link 13 connected withthe lever, a link 14 connected with the member, a rotatable connection15 between adjacent ends of the links 13 and 14 which, when rotated,varies the eective overall or combined length of the links 13 and 14 anda connection 16 between the lever 10 and the member 15 whereby themember 15 is partially rotated upon each operation of the lever.Theconnection 16 is engaged with the lever 10 at a point 17 spacedlongitudinally of the lever from the point of connection of the link 13therewith. In the present instance, this connection is disclosed asbeing remote from the pivot 11 of the lever 10 with respect to the pointof connection of the link and accordingly the connection 1.6moves'tlirough a greater distance upon operation of the lever 1() thanthe link 13 will move, .thus

providing the extra motion necessary to rotation of the rotating part15. It will, however, be obvious that the connection 16 could be engagedwith the lever `10 between the pivot 11 and the point of engagement ofthe link 13 therewith and still provide this difference of distance ofoperationnecessary to accomplish rotation of the member 15. Theconnection disclosed is, however, preferred for the reason that with aconnection such as last described, a thrust in opposition to thedirection of movement of the lever is set up decreasing the eiciency ofoperation.

ln addition to the foregoing structure, means are provided forpreventing return rotation of the member 15 when this rotation hasexceeded a predetermined amount. ln the present construction, therotating member 15 is provided with an arcuately curved face 18 `formedwith ratchet teeth 19 of a desired length and the link 14 has pivotallyengaged therewith a dog 20 for coaction with these ratchet teeth. In thepresent construction, the link 14 is shown as having its forward endbifurcated to form arms 21 between which the rotating member 15 eX-tends andby which the pivot dog 20 is supported. This link 14 ispreferably formed of two sections 22 and 23, the irst of which bearsthearms 21 while the latter is provided at its rear end, as at 24, withmeans for engagement with the brake. These sections have their adjacentends connected by a turn buckle 25.

The link 13 is provided at its rear end with an eccentric strap 26receiving an eccentric 27 carried by and pivoted between the forwardends of the arms 21 of the section 22 of the link 14, as at 28. Thepivotal connection with the eccentric is spaced from the center of theeccentric and accordingly upon rotation of the eccentric, the eectivelength of the links 13 and 14 and the connection therebetween will bealtered. To the side of this eccentric are secured plates 29 theperipheries of which are formed with the arcuately curved faces 18 andteeth 19 for coaction with the latch dog 20. These plates are furtherprovided with a pair of opposed ears 30 pivotally receiving therebetweenthe rear end of the link 16, as at 31. rl`he link 16 is formed in twosections 32, 33, the former being engaged with the lever 10 and thelatter with the ears 30. The section 33 has its forward end in the formof a tube 34 slidably receiving the rear end of the section 32. Thesection 32 is provided with ratchet teeth 35 and the tube 34 with a pawl36 for coaction with these ratchet teeth. ln the form shown in Figure 5,the link 13 instead of being provided upon its rear end with theeccentric strap 26 is pivotally secured, as at 37, to a disk 38'at apoint adjacent the periphery of this disk while the forward ends of thearms 21 are pivotally engaged with the disk at the axis thereof, asindicated at 39. The rear end 33 of the link 16 is pivotally engagedwith the periphery of the disk, as at 40, and this periphery' is formedwith the teeth 19 'for coaction with the dog 2O of the link 14.

The operation of the device is a follows When the lever 10 is moved inthe direction of the arrow A, the links 13, 14, are shifted in thisdirection a distance proportionate to the degree of movement of thelever. At the same time, the link 16 by its engagement with theperiphery of disk 29 or single disk 38 will cause a rotation thereof inthe direction of the arrow B of Figure 1, and this rotation willlikewise be proportionate to the amount of movement of the lever. lf thelever .10 is moved through a predetermined distance, the dog 20 willpass over the shoulder of one of the teeth 19 and will prevent returnmotion of the rotatable member 15 and retain the links 13 and theconnection represented thereby in their shortened relation. When thelever isreturned to its normal position, as in a majority of structures,it is returned by a spring, it will be obvious that the section 32 ofthe link 16 will move into the tube 34 and this link will have itssections maintained in this shortened relation by the engagement of thedog 36 with the teeth 35. This shortening movement will continue untilthe two sections of the rotating member 15 and link 16 have been takenup.

It will, of course, be obvious that it is notI contemplated that such anoperation shall take place at each operation of the lever 10 but'that itshall only take place when the lever 10 is moved to its fullest extent.Thus in the operation of a brake, the length of r the teeth 19 will beso computed that this Operation only takes place when the lever 10 hasbeen moved to practically the fullest extent possible. When the twosections have been completely taken up, the dogs 36 and 2O are releasedand the parts permitted to return to the position where the links 13,14, have their greatest overall length. The link 14 is then shortened asto effective length by use of the turn buckle, thus returning theapparatus to its original condition. Conteinplation of the structure ofFigure 5 will render it obvious that instead of the disk employed, anordinary crank could be eniployed with equal facility but since pivoteddisks have long been considered as the equivaleiit of a crank whenconnected, as disclosed, no illustration of this stiucture has beenmade.

Other advantages and modications being possible in the structurehereinbefore set forth, we do not limit ourselves to such specificstructure except as hereinafter claimed.

Vile claim 1. fl. slack take-up connection between a lever and a memberto be shifted thereby including a link connected with the lever, asecond link connected with the member, a connection between the firstand second links rotatably engaged with each thereof and when rotated,varying the combined overall length of the links and a third linkconnecting the rotating member and lever at a point spacedlongitudinally of the lever from the point of' connection of the firstnamed link therewith.

2. A slack take-up connection between a lever and a member to be shiftedthereby including a, rotating part which, when rotated, varies theeective length of the connection, a connection between the rotatablepart and lever partially rotating the same upon each operation of thelever, means for preventing return rotation of the rotatable part whenthe same has been rotated a predetermined distance and means for varyingthe length of the connection between the rotatable part and lever tocompensate for the 4 lil . second link connected with links rotatablyengaged with each thereof and when rotated, varying the combinedoverallllength of the links, and a third llink connecting the rotatingmember and lever at a point spaced longitudinally ,of the lever from thepoint of connection of the rst named link therewith, said link beingformed in two sections telescopically enga ed and having v ratchetengagement wit one another.

4. A slack take-up connection between a lever and a member to be shiftedthereby including a rota-ting part which, when rotated, varies theeiective length of the connection, and a connection between therotatable part and lever partially rotating the same upon each operationof the lever, ccmprising a link formed in two sections telescopicallyengaged and having ratchet con-a nection with one another.

5. A slack take-up connection between a lever and a member to be shiftedthereby in cluding a link connected with the lever, a the member, amember rotatably engaged with the free end .of the rst named link andwith which the second link isrotatably engaged at a point spaced fromthe point of connection of the rotatable member with the first namedlink and a third link pivotally engaged with the rotatable member at oneend and at its opposite end with the lever.

6. A slack take-up connection between a lever and a member to be shiftedthereby includin a link connected with the lever, a second llnkconnected with the member, a member rotatably engaged with the free endof the rst named link and with which the second link is rotatablyengaged at a point spaced romthe point of `connection of the rotatablemember with the first named link, a third link pivotally engaged withthe rotatable member at one end and at its opposite end with the lever,said rotatable member being provided upon its periphery with ratchetteeth, the second link having a do for coaction with said ratchet teethan means for automatically shortening the third link to compensate forch-anges of position of the pointof its connection with the rotatablemember with respect to the lever.

7. A slack take-up connection betweena'Y spaced from the point ofconnection of the' rotatable member with the first named link, a thirdlink tatable member at one end and at its opposite end with the lever,said rotatable member being provided upon its periphery with ratchetteeth, the second link having a do for coaction with said ratchet teethan means for automatically shortening the third link to compensate forchanges of osition of the point of its connection with the rotatablemember with respect to the lever, the third link being formed in twosections, said compensating means including a dog carried by one of thesections and engaging ratchet teeth formed upon the other of thesections.

8. A slack take-up connection between a lever and a member to be shiftedthereby including a rotating part which when rotated, varies theeffective length of the connection, a. connection between the rotatablepart and lever partially rotating the same upon each operation of thelever, means for preventing return rotation of .the rotatable part whenthe same has been rotated a predetermined distance, means for varyingthe length of the connection between the rotatable part and lever tocompensate for the shifting of the rotatable part and manually operab emeans for varying the effective len h of the connection.

n testimony whereof we hereunto a'ix our signatures.

DUN CAN M. RUSSELL. JAMES BUCHANAN.

pivotally engaged with the ro

